This invention relates to a photocurable pressure sensitive adhesive coated on a polyolefin base film that is used in the manufacture of semiconductor devices.
A semiconductor wafer, such as one prepared from silicon or gallium arsenide, is initially manufactured in a size larger than is used for the individual semiconductors. The wafer is typically thinned by grinding, and cut into small individual semiconductor dies, which are then transferred and adhered to the desired substrates. To support the wafer during these operations, and to streamline the process of bonding the die to the desired substrate, the wafer is adhered to a support tape that has a die bonding adhesive layer and a pressure sensitive adhesive layer, with the pressure sensitive adhesive layer situated between the adhesive layer and the support tape.
After the manufacturing operations, the pressure sensitive adhesive layer is cured and hardened by UV irradiation so that it releases from the adhesive layer that will be used for die bonding. In these operations, controlling the adhesion of the pressure sensitive adhesive so that it adheres tightly before photocure and releases cleanly and easily after photocure is important. The capability of releasing cleanly after cure is particularly important for subsequent fabrication steps. Conventional UV curable pressure sensitive adhesives do not always achieve a clean separation, thus creating a need for adhesives for use in semiconductor fabrication with improved release performance.